Hydraulic oil compositions



Unitcd States PatcntO The present invention relates to hydraulic oil compositions; more particularly it concerns hydraulic oil compositions based on chlorinated paraffin, chlorinated diphenyl, chlorinated terphenyl and/or alkyl, aryl or alkylaryl esters of acids of phosphorus.

According to the present invention the properties of the said hydraulic oil compositions can be improved by the addition of polyethers or polyether esters containing etheroxygen atoms in the main chain or by the addition of polyesters.

Suitable polyethers are, for example, those obtainable by polymerisation of 1,2- and/or 1,3-oxido compounds, by polycondensation of glycols or glycol mixtures, by reaction of glycols and glycol mixtures with aliphatic dihalogen compounds or by reaction of monoor polyhydric alcohols with 1,2- and/or 1,3-oxido compounds.

Suitable polyether esters are, for example, those obtainable by reacting polyethers still carrying free hydroxyl groups or other appropriate reactive substituents with monocarboxylic acids.

Polyethers or polyether esters which have proved especially useful are those which contain -(CH -O groups, for example compounds which are obtainable by polymerisation of tetrahydrofuran or of mixtures of tetrahydrofurane and 1,2-0xido compounds, if desired, by further reaction of polyethers or polyether esters containing exchangeable halogen, with alkali metal compounds of alcohols, 1,2-, 1,3- or 1,4-glycols, phenols, or carboxylic acids. In this connection, there may further be mentioned the compounds obtainable by condensation of 1,4-buty1ene glycol with itself or with 1,2- or 1,3-glycols or with 1,2- or 1,3-oxido compounds as well as the compounds obtainable by reaction of 1,4-dichlorobutane, a-dichlorodibutyl ether or Ii-dichlorobutoxybutane with 1,2-, 1,3- or 1,4-glycols; in addition, compounds may also be included which are obtainable from the aforesaid compounds, provided that they still carry free hydroxyl groups, by esterification with mono-basic carboxylic acids.

By the term polyesters those compounds are to be understood in the present case which are prepared from dicarboxylic acids and glycols or polyether glycols; besides, the polyesters include compounds which are produced with the additional use of other polyhydric alco hols, such as trimethylolpropane, or monohydric alcohols and/or monocarboxylic acids.

Suitable are also such polyethers, polyether esters and polyesters wherein ether-oxygen atoms are partly replaced by sulfur atoms.

Compounds of the type which may be considered as additives are described, for example, in German patent specifications Nos. 741,478, 766,208, 883,506, 893,390, 914,438, and German Patent 1,045,662, in US. patent specifications Nos. 1,976,678, 2,425,755, 2,425,845, 2,559,- 510, 2,570,037, in British patent specifications Nos. 642,- 037, 659,103, and 716,339 as well as in French patent specification No. 898,269.

With the aid of the proposed additives it is possible, inter alia, to improve substantially the viscosity index of the aforesaid hydraulic oils and their lubricating properties. For this purpose it is advantageous to add compounds of a suitable type whose molecular weight is above 1000. Suitable proportions are easily ascertainable in Ice each case by preliminary experiments; in general, it is sufficient to add quantities of l-lO percent by weight, referred to the hydraulic oils used.

Compared with additives of polybutenes, polymethacrylates or alkylated polystyrenes which have already been proposed for the aforesaid hydraulic oils, the compounds to be added according to the invention are distinguished in that they show a surprisingly high stability under continuous shearing stress on the hydraulic oils.

The good compatibility of the additives proposed according to the invention with other additives commonly used for hydraulic oils is also remarkable; these include for example, anti-ageing and anti-foaming agents, thickeners, anti-corrosivcs, agents for improving the capacity of separating water, or extreme pressure additives.

The following examples serve to illustrate the present invention without, however, limiting the scope thereof; the parts given are by weight.

Example 1 [Viscosity oi the diphenylcresyl phosphate in centistokes] without with addi- Temperature, 0. addition tion of the of the polyether polyether Viscosity index +43 +124 Example 2 [Viscosity of the trichlorodiphenyl in centistokes] without with addi- Temperature, 0. addition tion of the of the polyether polyether Viscosity index 290 +79 The tetrahydrofurane polymerisation product was prepared in the following manner:

1440 parts of tetrahydrofurane, 7.4 parts of the boron fluoride compound of tetrahydrofurane and 3 parts of 1,2-buteneoxide were polymerised at 0 to 5 C. according to Example 2 of German patent specification No. 741,478. The reaction mixture which became viscous, was kept stirring by slow addition of 1990 parts of chloroaera e-yea benzene; after standing at to C. for five days, the mixture was treated with 20 parts of triethanolarnine and 5 parts of phenyl-fl-naphthylamine. The components which were volatile up to a temperature of 200 C. and at a pressure of mm. Hg were then removed from the reaction mixture by distillation under reduced pressure.

Example 3 A mixture is used as hydraulic oil Which was prepared by treating at 5060 C. a mixture of 50 parts of hexachlorodiphenyl, parts of pentachlorodiphenyl and parts of trichlorobenzene, with 5 parts of the polyether described in Example 1.

The viscosity index of the original mixture is substantially improved by the addition of the polyether.

[Viscosity of the mixture in centistolres] Example 4 A mixture of parts of tetrachlorodiphenyl and 50 parts of diphenylcresyl phosphate, which is intended to be used as hydraulic oil, is treated at 70 C. with 5 parts of the polyether indicated in Example 1. The viscosity index of the original mixture is substantially improved by the addition of the polymer.

[Viscosity of the mixture in centistokes] Without with addi- Temperature, 0. addition tion of the of the polyether polyether S2. 4 201, 0 23. 9 57. 9 13v 3 32 l 3.3 7t 2 Viscosity index 113 +91 Example 5 In a mixture of 50 parts of tetrachlorodiphenyl and 50 parts of diphenylcresyl phosphate, which is intended to be used as hydraulic oil, there are dissolved at 50-60 C. 5 parts of a polyether of an average molecular Weight of 5000 prepared according to Example 1 of German patent specification No. 914,438 from tetrahydrofurane, ethylene oxide and 1,2-propylene oxide in a molecular L part of chlorinated natural rubber, a 20 percent solution in butanol and xylene (95:5) having a viscosity of about 90 centistokes, is subsequently added at 80 C.

The viscosity index of the original mixture is substan- 5 tially improved by these additives.

[Viscosity of the mixture in centistokesl without with the Temperature, C. the addi additives 10 tives Viscosity index ll3 +88 Example 7 20 A mixture is used as hydraulic oil which was prepared by dissolving in 97 parts of diphenylxylenyl phosphate at 4050 C. 3 parts of a polyether ester which was obtained by esterifying the polyether of Example 5 containing terminal free hydroxyl groups with butyric acid.

'The viscosity index of the diphenylxylenyl phosphate is substantially improved by the addition of the polyether ester.

30 [Viscosity of the diphenylxylenyl phosphate in centistokes] Temperature, C.

Viscosity index 40 Example 8 A mixture is used as hydraulic oil which was prepared by dissolving in 95 parts of diphenylxylenyl phosphate at 4050 C. 5 parts of a polyester of adipic acid and ethylene glycol having an average molecular weight of 450.

The viscosity index of the diphenylxylenyl phosphate is substantially improved by the addition of the polyester.

[Viscosity of the diphenylxylenyl phosphate in eentistokesl ratio of 3:3:2 with the use of 1 mol percent of the boron 55 t (I I trifiuoride compound of tetrahydrofurane. The viscosity Temperature, 0 g, 32 185 of hi i nih index of the original mixture is substantially improved by f P013" polytether the addition of the polyether. et er ester es er [Viscosity of the mixture in ccntistokes] 4 5g 5 19. 6 23.2 12.0 1 .8 without with addi- Temperature, C. addition tion of the 49 ig ifi @013 other Viscosity index +3 a 57.1 7; Q 1&6 3L4 example 3.3 7.0 vlscosltyindex +83 A mixture 13 used as hydraulic Oil which was prepared Example 6 In a mixture of 50 parts of tetrachlorodiphenyl and 50 parts of diphenylcresyl phosphate, which is intended to be used as hydraulic oil, there are dissolved at 60'70 C. 5 parts of the polyether described in Example 1. 0.1

by dissolving in parts of diphenylxylenyl phosphate at 40--50 C. 5 parts of a polyester having an average molecular weight of 2000 which was prepared from adipic acid and diethylene glycol with the addition of a small amount of trimethylolpropane.

The viscosity index of the diphenyixylenyl phosphate is 75 substantially improved by the addition of the polyester.

[Viscosity of the diphenylxylenyl phosphate in centlstokes] without with addiaddition of tion of the the polypolyether other ester ester Temperature, C.

Viscosity index Example [Viscosity of the mixture in centistokes] with addition of the polyether ester without addition of the polyether ester Temperature, C.

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Viscosity index --113 Example 11 without addition of the polyether ester with addition of the polyether ester Temperature, 0.

Viscosity index Example 12 A mixture is used as hydraulic oil which was prepared by dissolving in 97 parts of diphenylcresyl phosphate at 40-50 C. 3 parts of a polyether ester which was obtained in the following manner: 14.3 moles of polypropylene glycol of an average molecular weight of 1000 were reacted with 29 moles of adipic acid and the free carboxyl groups still present in the reaction product formed were esterified with a mixture of 11.4 diethylene glycol and 5 moles trimethylol propane.

The viscosity index of the diphenylcresyl phosphate is substantially improved by the addition of the polyether ester.

[Viscosity of the diphenylcresyl phosphate in centistokes] with addition of the without addition of the polyether ester Temperature, O.

Viscosity index The viscosity index was determined in all examples according to Zerbe, Mineraloele und verwandte Produkte (1952), pages 32-38.

We claim:

1. A hydraulic fluid consisting essentially of (a) at least one member selected from the group consisting of triehlorobenzene, chlorinated diphenyl containing at least three chlorine atoms, diphenylcresyl-phosphate and diphenyl-xylenyl-phosphate, and (b) at least one member of the group consisting of a polyoxyalkylene diol whose oxyalkylene groups are -(CH -O- groups, polyoxyalkylene diol whose oxyalkylene groups are groups and (CH -O- groups, polyoxyalkylene diol whose oxyalkylene groups are -(CH O-- groups, (CH -O-- groups and -CH(CH )--CH -O-- groups, polyoxyalkylene diol whose oxyalkylene groups are -(CH O groups and whose hydroxyl groups are esterified by low molecular weight aliphatic monobasic carboxylic acids, polyoxyalkylene diol whose oxyalkylene groups are --(CH -O-- groups and (CH 0 groups and whose hydroxyl groups are esterified by low molecular weight aliphatic monobasic carboxylic acids, and polyoxyalkylene diol whose oxyalkylene groups are --(CH;,) O groups,

groups and -CH(CH )-CH O- groups and whose hydroxyl groups are esterified by low molecular weight aliphatic monobasic carboxylic acids, the molecular weight of the polyoxyalkylene diols ranging from 5,000 to 12,000 and the ratio of the components (a) to the components (b) being 10:1 to :1.

2. A hydraulic fluid according to claim 1 consisting of approximately 96 percent by weight of diphenylxylenyl phosphate and approximately 4 percent by weight of a polyether of an average molecular weight of 5000 obtained from tetrahydrofurane, ethylene oxide and 1,2- propylene oxide in a molecular ratio of 3:3:2.

3. A hydraulic fluid according to claim 1 consisting of approximately 47 percent by weight of tetrachlorodiphenyl, approximately 47 percent by weight of diphenylcresyl phosphate and approximately 6 percent by weight of a polyether of an average molecular weight of 5000 obtained from tetrahydrofurane and ethylene oxide in a molecular ratio of 3 :4.

References Cited in the file of this patent UNITED STATES PATENTS 2,521,402 Osborn Sept. 5, 1950 2,543,735 Stewart et a] Feb. 27, 1951 2,559,510 Mikeska et a1 July 3, 1951 2,570,037 Smith et a1 Oct. 2, 1951 2,707,176 Gamrath et a1 Apr. 26, 1955 2,934,501 Moreton Apr. 26, 1960 FOREIGN PATENTS 534,111 Canada Dec. 4, 1956 681,357 Great Britain Oct. 22, 1952 OTHER REFERENCES The Preparation of Tetrahydrofuran Polymers as a Synthetic Lubricant for Metals, publ. by US. Naval Technical Mission in Europe T.L.R. No. 123-45(s), July 5, 1946, pages 1-7. 

1. A HYDRAULIC FLUID CONSISTING ESENTIALLY OF (A) AT LEAST ONE MEMBER SELECTED FROM THE FROUP CONSISTING OF TRICHLOROBENZENE, CHLORINATED DIPHENYL CONTAINING AT LEAST THREE CHLORIDE ATOMS, DIPHENYCRESYL-PHOSPHATE AN DIPHENYL-XYLENY-PHOSPHATE, AND (B) AT LEAST ONE MAMBER OF THE GROUP CONSISTING OF A POLYOXYALENE DIOL WHOSE OXYALKYLENE GROUPS ARE -(CH2)4-O-GROUPS, POLYOXYALKYLENE DIOL WHOSE OXYALKYLENE GROUPS ARE 